Removable denture



y 1949- R. J. MANIOLA 2,469,339

REMOVABLE DENTUREL Filed Sept. 16,.1947 2 Sheets-Sheet 2 INVENTOR.

Foes/er J. M/V/MA, M5.

Patented May 3, 1949 UNITED STATES PATENT OFFICE REMOVABLE DENTURE Robert J. Maniola, deceased, late of Chicago, 111., by James J. Maniola, administrator, Chicago, 111., assignor to James J. Maniola, Chicago, 111.

Application September 16, 1947, Serial No. 774,335

14 Claims. 1

This invention relates to improvements in dentures, and particularly to that class of dentures intended to be applied more or less permanently to an edentulous space, either in an anterior or posterior position in the mouth, and either to the upper or lower set of teeth.

This invention is, in certain respects, an improvement over that disclosed in the applicants application for removable dentures, Serial No. 744,205, filed April 26, 1947.

One object of the invention is to provide improved dentures which utilize the natural undercuts of the abutment teeth, whether anteriorly or posteriorly located, for retaining the denture in proper position within the edentulous space.

Another object of the invention is to provide a denture which is adapted to seat in an edentulous anterior or posterior area defined by natural undercut mesial and distal surfaces of the abutment teeth and which avoids the formation of objectionable food traps or cavities by closing all the interproximal spaces spanned by the denture.

An additional object of the invention is to provide a denture of at least three cooperating parts which are separately insertable into the edentulous area or space for which they are made and which, when secured in said area or space, closely contact the mesial and distal surfaces of the abutment teeth for retention in position against vertical and lateral displacement.

A still further object is the provision of a denture of three cooperating parts which are separately insertable into the edentulous space in a predetermined consecutive order, the last-insertable part being an artificial tooth securable to one of the previously-insertable parts and being effective to maintain all three parts firmly in the space for which they are made.

Other objects of the invention relate to various features of construction which will be apparent from a consideration of the following specification and accompanying drawings, wherein Figure 1 is a broken lower plan view of a set of upper teeth;

Fig. 2 is an elevation of the teeth of Fig. 1 as viewed from a position indicated by line 22 of Fig. 1 and showing an artificial denture in place;

Fig. 3 is a view similar to Fig. 2 but illustrating the last-insertable part comprising the keying tooth in position in broken lines and in a removed position in full lines;

Fig. 4 is a view also similar to Fig. 2 but showing only the first-insertable section of the denture in position in the edentulous space and the second-insertable section in a removed position;

Fig. 5 is a sectional view taken on line 5-5 of Figs. 1 and 2;

Fig. 6 is a broken, enlarged, partially sectioned, buccal view of the denture in longitudinal section and showing the relation thereof to the two abutment teeth;

Fig. '7 is a persepective view of the three parts of which the denture is formed, the parts as shown being separated and inverted;

Fig. 8 is a view similar to Fig. 6 but illustrating an embodiment in which only one of the abutment teeth is mesially or distally undercut;

Fig. 9 is a broken lower plan view of a set of upper teeth illustrating another embodiment of the present invention and showing how the invention may be applied to an anterior position in the mouth, that is to replace front teeth;

Fig. 10 is an elevation of the teeth of Fig. 9 as viewed from a position indicated by the line Ill-I0 of Fig. 9 and showing the firstand second-insertable parts in assembled position within the edentulous space and the third-insertable part comprisingthe key-tooth illustrated in assembled position in broken lines and in removed position in full lines; Fig. 10 corresponds to the view shown in Fig. 3 for the first disclosed embodiment;

Fig. 11 is a View similar to Fig. 10 but illustrating the first-insertable part in assembled position and the second-insertable part in removed position;

Fig. 12 is a sectional view taken on line l2-l2 of Fig. 9;

Fig. 13 is a sectional view taken on line l3-l3 of Fig. 11;

Fig. 14 is a sectional view taken along the line I4--l4 of Fig. 9;

Fig. 15 is a fragmentary, enlarged, partially sectioned lingual view of the denture as seen along the line 15-15 of Fig. 9; and

Fig. 16 is a perspective view of the three parts of which the denture is formed, the parts as shown being separated and inverted.

The embodiment shown in Figs. 1 through 8 will first be described; then the embodiment shown in Figs. 9 through 16 will be described.

In the drawings, Figs. 1 through 8, a set of natural upper teeth are shown, two posterior teeth having been replaced by a denture that is illustrative of one embodiment of the present invention. The two natural teeth that have been removed are the second right bi-cuspid and the first molar. Hence, the abutment teeth for the edentulous area caused by the removal of the two natural teeth are the first right bi-cuspid l0 and 3 the second right molar H. As indicated, particularly in Fig. 6, the distal surface of tooth Ill and the mesial surface of tooth II are undercut surfaces, that is, each converges generally toward the root tip of the respective tooth. These surfaces are usually naturally undercut in this man ner due to the characteristics of teeth to be broader at the occlusal or biting surface than at the root; where desired, this undercut can be suitably modified artificially, by grinding. These undercut surfaces have been a source of trouble in makin conventional removable partial dentures that avoid the formation of food traps, but such undercut surfaces are utilized in the; present improvements for retention. of the dentures in.

place and without the use of bars and clips of the types that hereto-fore commonly have been used.

The denture illustrated in Figs. 1 to 7 comprises three coacting parts, namely, sections A and B which are insertablein the edentulous; area in the order named and the keying-tooth C which is. securable to A, asby cementing, to-hold. the assembled denture securely in place. Fig. 7' illustrates the parts A, B, and C as viewed from the; left in Fig. 1, that is from the buccal side, and also shows the-parts in inverted relation, Fig. 1 being a view of the upper set of teeth- The section A is a casting, of;metal or a molding; of ap-' propriate plastics material andcomprises a sur face l2 saddle-shaped in; accordance with the. gum surface or ridge portion: over which it is. to. be worn, as indicated in- Fig. 5.. The body portion l-3- of section A has formed: thereon a vertical portion or pillar' l5, provided. with a wall or surface i6 that ismolded oncast to conform. to-the. mesial surface- I-l. of the abutment tooth H. Hence, the wall IE is not only curved. in horizontal cross-section generally to conform to the shape of. the mesialsurface of tooth H withwhich the surf-ace l6 contacts, but it is inclined from the vertical reciprocally with respect to:the undercut. mesial surface of" tooth. ll. In Fig. S-the. relation. of the surface t6. of the section A to the mesial.

undercut surfaceil of tooth Ll? is: clearly. indi- 1- cated.

The pillar I is provided with a rearward]y,v

that is, distally, directedlug l8; adapted. to seat. in

arecess that may be-groundg. necessary, in the: occl-usal surfaceof; the tooth llasindicated at. The forward or mesial surface. 20.;

It in Fig. 6. of the pillar 6-5: is disposed, in. a plane that. will accommodate insertion of the section B in ,-a direca tion parallel to the median line: of. the'u-ndelcut distal surface 2| of the abutment tooth H}.- aswill.

be: more fully described hereinafter. That. is, the lines X and Y, which represent the mediarrlines of the surfaces 2dand- 2 l respectively, should: be

either parallel. or upwardly convergent. as viewed tacting surface l2 shaped in conformity with thecontour of the portion of the gum ridge over which it is to seat; and sectionB is provided with av similargum contacting surface 24. The mesial surface 25 of the section. B isinclined complementarily with respect to the undercut distal surface 2! of the tooth l0 and transversely corresponds to the transverse curvature or contour of the tooth while the distal end of section B has a surface 26 that is inclined for contact with the surface 24] of section A. The mesial end portion of the section B, as shown, also is provided with a lug Z'l, that extends mesially onto. :a seat 28, ground if necessary, in an occlusal surface of the abutment tooth H) as indicated in Fig. 4.

The artificial teeth C and 22 are secured to the sections A and B by any approved means, such as by pins or studs 29 formed integrally with the respective section in the casting or molding thereof and which enter bores or recesses 30 provided in the teeth. Cement maintains the teeth in proper relation.

The two surfaces l2 and 24 respectively of sectionsA and B provide substantially a continuous ridge-contacting and ridge-conforming surface when the-sections are" assembled'within the edentu-lous space.

As will be apparent from the foregoing, the sections A and B are moulded or cast to fit the edentulous area of a particular patient and hence all sections A and B of the improvements will not beof the precise shape shown, in the drawings nor will the angles and cross sectional shapes of. the distal and mesial surfaces of the denture be precisely as illustrated. The distal and mesial surfaces of the abutment teeth however, or at least one of such surfaces, must be of: an undercut form for taking full advantage of the present improvements.

In placing the. sections A and B into operative position, the section. A is first placed in-the edentulous-space with thelug 18 upon the seat l9 and with thewall l5 contacting the mesial wall IT of the tooth H.

The section B' is next placed in position and may be moved into proper position in a direction parallel to the medial line. of either surface'20 or' 2! since, as above described, these surfaces are disposed at angles to'permit' such movement. In pressing the sectionB'into position, the wedging action of wall 213 on wall 2.6i tends tourge the sections longitudinally in opposite directions and thereby effect close inter-engagement of the surfaces l6--l'l and 2|-- 25, respectively, the lug 21 of section B being positioned upon its seat 28.

As best shown in Fig. 6, the key-toothlC, when cemented in place, is in line to-block vertical displacement of they section B, by engagement withthe surface 3| thereonj and, because section Bi overlies section A at surfaces 20-26, section B is in line to block vertical displacement of section A. Thus, with C cemented in place, none of the parts are individually displaceable. Furthermore, due to the reciprocal relation between surfaces lin -Hand 2l-25, both of the surfaces l1 and 2| being undercut, the assembled denture is not displaceable asa unit out of the edentulous space.

The lugs l8 and 27 receive the gum-wisezthrust of the teeth. C and, 22 in biting or chewing and thus-relieve the gum ridges fromexcessive pressure. The lugs also restrain rocking movement of the denture withrespect to theridge of the gums as an axis, and.cooperate-withthearcuate, gum fitting lower surfaces [2 and 24' of. the secticns A and B, as Well as with the arcuate. shape of the mesial and distal surfaces of the denture (which closely contact the respectife surfaces of the. abutment teeth). in inhibiting lateral displacementof the. denture, that islingually or buc- 'cally. The movement of the denture in an axial direction, that is, away from the gum surface on which the denture fits, is restrained by the coaction of the end walls I6 and 25 of the sections A and B with the respective contacting undercut walls of the abutment teeth.

Fig. 8 illustrates the adaption of the structure shown in Figs. 1 to '7 inclusive to an edentulous area having but one undercut tooth surface, indicated at IT. The opposite end of the surface is defined by an abutment tooth l having a vertical surface 36. The denture shown in Fig. 8 is in all respects similar to the denture above described except as modified for coaction with the tooth indicated as IE1 which has a vertical rather than an undercut surface. The cooperating surface 31 of the section A conforms to the surface 35. Assuming the parts are assembled as described in connection with the form shown in Figs. 1 to '7, that is by inserting A, B and C", in that order, and cementing C in place, the den ture of Fig. 8 will not move vertically by gravity (assuming it is an upper denture) since any vertical movement would cause the undercut surface I? of tooth I I to effect a wedging action on the complementary surface I5 of section B, the component of which would tend to force the denture to the right as viewed in Fig. 8. Such movement, however, is resisted by the abutment tooth It. Likewise, the right-hand end of the denture shown in Fig. 7 cannot swing downwardly about the lug I8 of section B as a pivot for the reason that no clearance for such arcuate movement is present within the edentulous area.

It will be seen that one or both of the denture sections may be provided with more than one tooth where the edentulous area requires a greater number of teeth than that shown, or with a single tooth in one and no tooth in the other. It will also be apparent that the improved denture, having the two sections A and B arranged in endto-end relation, is retained as a unit against vertical displacement by reason of the action between the respective contiguous surfaces of the abutment teeth and the remote ends of the denture sections which are reciprocally or complementarily shaped to conform to or mate with the respective surfaces of the teeth. It will also be apparent that slight movement of the sections A and B in axial directions may occur as section B is pressed into firm position in the edentulous space due to the coaction of the reciprocally shaped inclined faces and 26 which tends to move the sections in opposite directions against the respective teeth ID and II. The close-fitting relationship of the remote end portions of the denture and the abutment teeth avoids the formation of food traps or cavities between the abutment teeth and the adjacent artificial teeth since the respective inter-proximal spaces are closed by the adjacent portions of the denture sections A and B. Likewise, since the inclined surfaces 26 and are reciprocally formed, they closely interfit and exclude food particles from between the same and since they are retained in such interfitting relation by the blocking action of the key-tooth they, in turn, retain the remote ends of the sections in close contact with the abutment teeth.

Another form of the invention, applicable particularly to anteriorly positioned dentures, such as incisors, is illustrated in Figs. 9 to 16 inclusive and will now be described. A problem in applying the previously described embodiment to the replacement of incisors arises because those teeth do not have concave occlusal surfaces for the retention of lugs such as I8 and 21 to restrain the denture against rocking movement about the gum ridge as an axis.

In Figs. 9 to 16, a set of natural upper teeth is again shown, two of which have been replaced by a denture illustrative of the present invention. The two natural teeth that have been removed are the first and second incisors on the right side. Hence, the abutment teeth for the edentulous area caused by the removal of the two natural teeth are the first left incisor HI and the third right incisor III. As indicated in Fig. 11, the mesial surfaces of teeth I it and H l are undercut surfaces, that is, each converges generally toward the root tip of the respective tooth in the manner previously described.

The denture illustrated in Figs. 9 to 16 comprises three coacting parts, namely, sections D and E which are insertable in the edentulous area in the order named and the key-tooth F which is securable to D, as by cementing, to hold the assembled denture securely in place. It will be apparent, as the description proceeds, that parts I D, E and F are, respectively, equivalents of parts A, B and C of the previously described embodiment. Fig. 16 illustrates the parts D, E and F as viewed lingually, somewhat from the left in Fig. 9, and also shows the parts in inverted relation, Fig. 9 being a view of the upper set of teeth. The section D is a casting of metal or a molding of appropriate plastics material and comprises a surface I l2 saddle-shaped in accordance with the gum surface or ridge portion over which it is to be worn, as indicated in Fig. 12. The body portion I I3 of the section D has formed thereon a wall or surface IIB that is molded or cast to conform to the mesial surface H! of the abutment tooth Ill. Hence, the wall H6 is not only curved in horizontal cross-section generally to conform to the shape of the mesial surface of tooth H! with which the tooth contacts, but it is inclined from the vertical reciprocally with respect to the undercut mesial surface of tooth l l i. In Fig. 11, the relation of the surfaces H5 and Ill is clearly indicated.

The body H3 of section D is provided with a sidewise, that is distally directed lug H8 adapted to seat on the lingual face of the abutment tooth II! as indicated in Fig. 15. The opposite or mesial surface I28 of the section D is disposed in a plane that will accommodate insertion of the section E in a direction parallel to the median line of the undercut mesial surface I2! of the abutment tooth I II] as will be more fully described hereinafter. That is, the lines W and- Z, which represent the median lines of the surfaces I29 and IZI, respectively, should be either parallel or upwardly divergent as viewed in Fig. 15. Hence. when the section D of this embodiment has been placed in position in the edentulous space, the two surfaces l2!) and Hit. having their median lines parallel or convergent in the direction of the roots of the teeth, will accommodate insertion of the section E.

Referring to Fig. 15 it will be seen that the sections D and E carry respectively the artificial teeth F and I22 which replace the natural teeth above mentioned. As stated, the saddle of section D, as shown in Fig. 12, has its gum contacting surface H2 shaped in conformity with the contour of the portion of the gum ridge upon which it is to seat; and section E is provided with a similar gum contacting surface 224i, as indicated in Fig. 13. The mesial surface I 25 of the section E is" inclined complem entarily with resp'e'ctto the undercut mesialsurface :21 of the tooth 1:10am transversely.corresponds to the transverse curvature or contour of the tooth while the distal end' of section has a surface rze that :is inclined for contactwith the mesial surface 129 of section D. The mesial end portion of the section 'Eis-also provided with a lug 2? that extends distally-onto the-lingual surface ofabutment tooth H0. The'two lugs H8 and l 21 thus bear on the inside surface of the abutment teeth to prevent outward displacement of the denture, aswell as to transmit biting load to the abutment teeth thereby relieving the gum ridge of the greater proportion ofeither of such loads.

The section E is provided with an extension 41 which preferably will "be molded or cast integral therewith and so formed as to 'lie flat against the palate to avoid a food trapping space therebetween. The extension 41 terminates in an anchor lug 42 '(Fig. '14) which is seated onto an occiusal seat 43 between a pair of teeth remote from the edentulous space, the anchor seat in this case being between the first and second bicuspids 44 and 45, respectively. The anchored extension 4| is efiective to prevent :theinward or lingual displacement of the denture and thus complements the functionof l the lugs li'iland i2! which prevent outward displacement as above described.

The artificial teeth F and 122 are secured to the sections D-and E respectively by any approved means such as by :pins or studs 129 formed integrally with the respective: section in the casting or molding thereof; lyingsubstantially parallelto the anterior surfaces of the sections, and which enter bores or recesses l30 provided in the teeth. Cement maintains the teeth in proper relation. As best shown inFigs. 12,13 and 15, the artificial tooth F is "formed with alingual'ly extending ledge 46 which overlies the edge d7 of section E thereby preventing parallel displacement of the latter when the tooth F is cemented in place.

The two surfaces -"ll2and 124, respectively, of sections D and E provide substantially a continuous ridge-contacting and ridge-conforming surface when the sections are assembled within the edentulous space.

As will be apparent fromzthe foregoing, the sections D and E are molded-ortcast to fit :the edentulcus area of a particular-patient and hence sections 1) and E of the'improvements will not be oi the precise shape shown "in the drawings nor will the angles and cross-sectional shapes of the distal and mesial surfacesof the denture be precisely as illustrated. The mesial surfaces of the abutment teeth, howevenor at least one of such surfaces, must be ofta natural or ground undercut form for taking full advantage of the present improvements.

In placing the sections D and E into operative position the section D is first placed the edentulous spacewith' the lug H8 seated upon the lingual surface'of abutment tooth Ill and with the wall INi contacting the mesial wall ll! of the tooth I I I. The section E is next emplace'd and may 'bemoved' to the proper position in a direction parallel to the medial line of either surface I20 or l2l since, as-above describedfthese surfaces are disposed at angles to'permit such movement. In placing thesection E into posi-- tion the wedging action ofwall 1'20 on wall I26 tends to urge the sectionslongitudinally in opposite directionswand thereby efiectclose interenga'gementpfv the surfaces MiG-+11 1 and nilrespectively, the'lug. .l 21' of section "E being seated upon the lingual face er abutment tooth Hi].

As-bes't shown in Fig. 15, the key-tooth when cemented in place, is' in line to block vertical displacement of the-section Ebyinterengagement of "surfaces- 16 and AJ; and, because section E overlies section D a-t surfaces l2ll l2t, section E isiin'line toblo'ckvertical displacement of section 1). Thus, with F cemented in place, none of the parts of thedenture is displaceable out of' the edentulous area-individually. Further more, due to the reciprocal relation between-the surfaces 1 |6-'-llT-and l2|l25, both of the surfaces H land I 2| 'be'ing undercut in this particular example, "the denture "is not :displac'eable "outxof the edentulous space,- as a unit.

'The 'lugsl l il and l2'l"receive the gum -wi'se thrust of the teeth F and I22 in' biting or chewing and thus relieve the gum ridges 'from excessivepressure. 1 The lugs also restrain anterior, that is forwardly outward, rocking movement of thedenture with respect to the ridge of the gum as .anzaxis. The extension, anchored as-descri-bedbetween 'the bicuspi'ds 44 and 45, cooperate with the 'arcuate 'gum-fittinglower surfaces H2 and 124' of the sections 3) and E, as well as -with thearcuate shape of themesial-and distal surface of the denture (which closely contact the respective surfaces of the abutmentteeth) in inhibiting lateral:displacem'entof the denture in the inward or lingual direction. I The movement of the denture in a vertical direction, that is, away from the gum surface on which the denture-fits-is restrained by the co -action of the end walls l lli and I25 of the sections D and E with the respective contacting-undercut walls of the abutment teeth. As describedin connection'with the embodiment-of Fig. 8, the em-bodimen't of Figs- 9 to 16 is likewise'usable'with an edentulous space having onlyone undercut abutment-tooth.

Furthermore, as also described in connection with the previous embodiments, itwill be apparent that one or both-of the denture sections D and E may be providedwith 'more than one tooth where the edentulous area requires a greater number of teeth than that shown, or with a single tooth'in one section andno tooth in the other.

From the foregoing description, it will be seen that the embodiment of Figs. 9 to 16 is'basic'ally the same as that previously described for the other embodiments,'with the lugs H8 and I2! being applied to the lingual rather than the occlusal surfaces of theabutment teeth, and with the anchored extension 4i effective to inhibit the inward displacement of the denture. Otherwise the basic structure is the same and provides the same advantages of avoiding the formation of food traps and eliminates the use of clips and bars-and the like,"-as=-"mentioned in'connection with the first described embodiments.

While I have shown and described'dentures that are illustrative of 'the'inven tion, various changes in the details shownmay'be made Withinthe spirit of the invention as covered by "the 'appended claims.

Iclaim:

1. A denture for use in an edentulous space defined by undercut walls of'two abutment teeth comprising a-pair of denture sections adapted to be positioned consecutively in said space and each provided with remote end walls reciprocally shaped with respect to and adapted "to contact the undercut surfaces-of the respective teeth,

"said sections being provided with interfitting adjacent end walls reciprocally shaped to urge the sections in opposite directions as the second of said sections is pressed into interfitting relation with the first section within said space for thereby urging said remote end walls into contact with the said surfaces of the respective teeth for restraining vertical movement of the denture from said space, and a keying member comprising an artificial tooth mounted on said denture effective to maintain said sections in position in said edentulous space.

2. A denture for use in an edentulous space defined by undercut walls of two abutment teeth comprising a pair of denture sections adapted to be positioned consecutively in said space and each provided with remote end walls reciprocally shaped with respect to and adapted to contact the undercut surfaces of the respective teeth, said sections being provided with interfitting adjacent end walls reciprocally shaped to urge the sections in opposite directions as the second of said sections is pressed into interfitting relation with the first section within said space for thereby urging said remote end walls into contact with the said surfaces of the respective teeth for restraining vertical movement of the denture from said space, and a tooth carried by said denture efiective to retain the adjacent ends of said sections in said interfitting relation.

3. A denture for use in an edentulous space defined by undercut walls of two abutment teeth comprising a pair of denture sections adapted to be positioned consecutively in said space in end-to-end relation, the remote ends of said sections being shaped reciprocally with respect to the respective undercut Walls, the adjacent ends of said sections being reciprocally shaped for interfitting contact upon the positioning of said sections in said space with said remote ends in contact with said walls, and means including an artificial tooth for securing said adjacent ends of the sections in interfitting contact and retaining said remote ends in contact with said walls and thereby restraining vertical displacement of the denture -from said space.

4. A denture for use in an edentulous space defined by undercut walls of two abutment teeth comprising a pair of denture sections adapted to be inserted consecutively in said space, the first insertable section having a tooth contacting end wall reciprocally shaped for contact with the undercut wall of one of said teeth and having an opposite end portion disposed at an angle at least as great as the angle of the undercut portion of the other abutment tooth, said second insertable section having an end wall shaped reciprocally with respect to the undercut wall of the latter tooth for contacting the same and having an opposite end wall portion disposed in a plane parallel to the plane of the second mentioned end portion of the first section and adapted to contact the same when the sections are in position in said space, and means for retaining said last mentioned end portions of the sections in contact for retaining the said tooth-contacting ends of the respective sections in engagement with the undercut walls of the respective abutment teeth,

said means including an artificial tooth carried by said first insertable section in a position with respect to said second insertable section to retain the latter in position within said edentuous space.

5. A denture for use in an edentulous space defined by undercut walls of two abutment teeth comprising 'a pair of separable sections insertable consecutively in end-to-end relation in said space, the first insertable section having an end wall reciprocally shaped for contact with the undercut wall of one of said teeth, the second insertable section having an end wall shaped reciprocally for contact with the undercut wall of the second tooth, the other ends of the sections having cooperating portions adapted for mutual contact when the sections are in position in said space and being arranged in planes enabling said second section to be inserted in said space in a vertical direction paralleling the plane of the undecut wall of said second tooth, and an artificial tooth secured to said second insertable section in position to key said first insertable section in place within the edentulous space.

6. A denture for use in an edentulous space defined by undercut walls of two abutment teeth comprising a pair of separable sections insertable consecutively in end-to-end relation in said space, the first insertable section having an end wall reciprocally shaped for contact with the undercut wall of one of said teeth, the second insertable section having an end wall shaped reciprocally for contact with the undercut wall of the second tooth, the other ends of the sections having cooperating portions adapted for mutual contact when the sections are in position in said space and being arranged in planes enabling said second section to be inserted in the space in a vertical direction paralleling the plane of the undercut wall of said second tooth and enabling said second section to restrain the first section from vertical displacement from its position in said space, and a tooth securable to said first section after the second section is in place in a position to block vertical displacement of the second section from its position in said space.

7. A denture for use in an edentulous space defined by undercut walls of two abutment teeth comprising a pair of separable sections insertable consecutively in end-to-end relation in said space, the first insertable section having an end wall reciprocally shaped for contact with the undercut wall of one of said teeth, the second insertable section having an end wall shaped reciprocally for contact with the undercut wall of the second tooth, the other ends of the sections having cooperating portions adapted for mutual contact when the sections are in position in said space and being arranged in planes enabling said second section to be inserted in the space in a vertical direction paralleling the plane of the undercut wall of said second tooth, and a keying member for holding said denture in said space comprising an artificial tooth securable onto one of said sections after both are in place in a position with respect to the other section toprevent vertical displacement of the latter from said space.

8. A denture for use in an edentulous space defined by walls of two abutment teeth comprising a pair of separable sections insertable consecutively in end-to-end relation in said space, at least one of said walls being undercut, the first insertable section having an end wall reciprocally shaped for contact with said wall of one of said teeth, the second insertable section having an end wall shaped reciprocally for contact with said wall of the second tooth, the adjacent ends of the sections having cooperating portions adapted for mutual contact when the sections are in position in said space and being arranged in planes enabling said second section to be inserted in the space in a vertical direction paralleling the plane aseaseo of said wall of said second tooth, and means for retaining said adjacent end portions or the sections in close mutual contact to maintain the denture in said space, said means including an overlapping of one of said sections with respect to the other at their adjacent end portions whereby said one section is effective to restrain the other section from vertical displacement out of the edentulous space, said means also including an artificial tooth secured to said other section a portion of which is positioned to block vertical displacement of said one section.

9. A denture for use in an edentulous space defined by walls of two abutment teeth, at least one of said walls being undercut, comprising a pair of denture sections adapted to be positioned consecutively in said space and each provided with remote end walls reciprocally shaped with respect to and adapted to contact said walls of the abutment teeth, said sections being provided' with interfitting adjacent, end walls shaped reciprocally with respect to one another and with said adjacent wall of one of said sections overlying the other to restrain the latter from vertical displacement, said one section having an extension anchored on a tooth other than the abutment teeth.

10. A denture for use in an anterior edentulous space defined by Walls of two abutment teeth, at

least one of said walls beingundercut, comprising a pair of denture sections adapted to be positinned consecutively in said space and each pro.- Vided with remote end walls reciprocally haped with respect to and adaptedto contact said walls of; the abutment. tee h, said ections being pr vided with interfitting adjacent end walls shaped reciprocally with respect to one another, one of said adjacent walls overlying the other to restrain the section carrying the l-atter from vertical displacement, said one section having an extension anchored on a posterior tooth remote from said abutment teeth.

11. A denture for use in an edentulous space defined by walls oftwo abutment teeth, at least oneof d Wal s being n lercu ,v compr a I pair of dent re-se ions adap ed to b po i con c tively in id. space and each provided with remote end. walls, reciprocally shaped with resp ct to and adapted o ntac said walls of the abutment teeth, saidisoctions being provided with interfitting adjacent end walls shaped recip.-- rooally with respect to one another and having said adjacent wall of one of said sections overlying the other o estrain thelatt r rom ertical displacement out of said space, said one section having an extension anchored on a tooth remote from said abutment teeth saiddenture having a Keying member comprising an artificial tooth securable thereto and having a gum-facing shoulder engageable with said, one section to restrain it from Verticaldi' pIaQement out of said space.

12,. A denturefor use in an anterior edentulous space defined by wall of two abutment teeth, at least one of said Walls being undercut, comprising a pair of denture sections adapted to be positioned consecutively in said space and each provided with. remote end wal s recip ocally s aped with respectto and adapted to contact said walls of the abutment teeth, said sections being provided with interfitting adjacent-end walls shaped reciprocally with respect to one another and having the adjacent wall. of one of said Sections overlying the other to restrain the latterfrom vertical displacement, one of said sections having an extension anchored in a posterior position re.- rnote from said abutment teeth and efiective to restrain inward or lingual displacement of said denture, and said denture having at least one portion engageable with a lingual surface of one of, the abutment teeth to restrain outward or anterior displacement of the denture.

l3. Aden ur o se in n e ent lo s spac defined by walls of two abutment teeth, at least one of said walls being undercut, comp isinga pair of denture sections adapted to be positioned consecutively in said space and each provided with remote .end walls reciprocally shaped with respect to and adapted to. contact they said walls of the abutment teeth, each of said sections also a g an extension ene aeablewi h one of aid a u t e th her i ing, o lting loads applied to said denture will. be transmitted to said abutment, teeth, a sec on b ing providodwith erfi ne ocally shaped adjacent and wall one of said secti ns hav ng ey ng; ooth securable thereto after both. sections, are as. sembled within said space and having a portion overlyingthe other section whereby it is effective to maintain both of said sections in. assembled positions Within said edentulous space,

1,4. A denture for use in an edentulous space defined by walls of two, abutmentteeth, at least one of said walls being undercut, comprising a pair of denture. sections adapted tobe positioned consecutively in said space and each provided with remote end walls. reciprocally shaped with respect. to andv adapted to contact the said Walls of the abutment teeth, each of said sections also having an .extensiOnadapted to fit into a groove in anocclusal surface of one of .said abutment teeth to transmit load. applied to saiddenture to said abutment teeth, said sections, being pro-. vided with interfitting reciprocally shaped. adjacent nd all one of which is hap d o ov lie the other, one of said sections having a keying tooth. attachable thereto after both sections are posi on Within said spa ndensaeeable w h both sections whereby it is effective. to maintain both .of said sections in. assembled positions withinfiahi edentulous, space.

J MESJ. MAN-IOLA. Administrator of the Estate of Robert J. M amola,

Deceased.

BEFEBENQES CITED IEhe following. references are of record in the file of this. patent:

UNITED STATES PATENTS Number Name Date 1,641,881 Goldfarb Sept. 6, 1927 2,111,787 Knowles Mar. 22, 1938 

